You can bet on almost anything. The entire science called astrobiology is betting that there is life somewhere other than Earth. What are the odds? Currently the odds on finding intelligent life are dropping. There is a betting office online based in England that will give odds on finding extraterrestrial intelligent life. It is called William Hill. They dropped the odds from 1000-1 to 100-1 when the first almost Earth-like exoplanets were discovered.
Is 100-1 overly pessimistic? Perhaps. In the early 1960’s they gave 1000-1 odds against a man walking on the moon by 1970. They paid out about 2 million dollars.
There are reasons for believing that life exists on other planets. A look at recent developments shows the chances of finding some form of alien life are increasing. It might not be time to bet the farm but the foolish gamble is to bet against it. Here are some of the reasons why.
There Are So Many Stars
If all of the factors required for life are probabilities, then the odds are alien life exists somewhere. One way to conceptualize this is the famous Drake equation. Frank Drake created this equation decades ago. It gives an estimate of the number of planets that have intelligent life at this time in our galaxy. A rough approximation of this equation is as follows. First, start with the total number of stars in the galaxy, say about 200 billion. Then reduce that number by the percentage that has planets. Then reduce that number by the percentage of those planets that are in a temperate zone. Then reduce again by the number of planets with life, then those with intelligent life. These are just guesses at this point in our scientific knowledge but we are fairly certain that the percentages are better than zero. In short, if you look at enough stars then you eventually come up with a number of planets where life could start.
In 1977, a radio astronomy site run by Ohio State University detected a large signal. It was a strong, narrowband signal and the wavelength was near 21 cm – the so called water hole of radio astronomy. The signal was strong enough that a researcher wrote “Wow” on the computer printout. It was never heard from again but it was never explained either.
What if a civilization sent a onetime signal in our direction? Ridiculous you say! But we did it. As described by Dr. Seth Shostak in his book “Confessions of an Alien Hunter”, in 1974, Frank Drake and his team used the Arecibo telescope to send a 210 byte message toward the globular cluster M13. It won’t get there for 25,000 years but when it arrives it will be a onetime event. The Russians did something similar in 2008 when it sent a signal toward the exoplanet Gliese 581c, at the time the most Earth-like planet found. So, very slowly, the odds of extraterrestrial life detecting us are increasing. At the recent SETIcon held in Santa Clara, CA this August, members of the SETI institute admitted that they have seen candidate signals but they could not be verified or reacquired.
Advanced Technology Looks like Magic
The Fermi Paradox says that if intelligent life exists, we should have seen them by now. This is still the best argument against the likelihood that we will talk to E.T. But it is true only if that intelligent life is far advanced. Arthur C. Clarke said that any sufficiently advanced technology would look like magic to us. So the answer to Fermi might be, “How do you know they aren’t here?”
Jill Tarter, Research Director at the SETI Institute, says “we’ve poorly explored our solar system. The sorts of things we could rule out are big, bright Starship Enterprise-like craft, and those only in a few locations. Anything dark, or small, or representative of space colonization by other than wet meat are not at all excluded.”
Catching Planetary Transits (us or them)
The NASA Kepler spacecraft is looking for Earth-like planets. It is looking at a section of the sky between the constellations Lyra and Cygnus. The idea is that planets passing in front of their star might reduce the amount of light we see from that star. This is called the “transit method” of exoplanet detection. But astronomers are now considering that E.T. might do the same thing. This means that the odds of an extraterrestrial intelligence deliberately sending a signal in our direction are greater if they can see the Earth against the background of the sun. The SETI Institute will make targeted studies of some of these stellar systems starting this summer. Meanwhile, Kepler is up to 700 planet candidates. One estimate is that half will turn out to be verified.
SETI Quest Answers a Wish
Dr. Jill Tarter gave a speech at the TED conference, an organization that brings together people from three areas: Technology, Entertainment, Design. Each TED conference speaker gets to make a wish. Tarter’s was “that you would empower Earthlings everywhere to become active participants in the ultimate search for cosmic company.” The realization of that wish is SETI Quest which will “help us maximize the potential of the fantastic Allen Telescope Array (the ATA, funded by Microsoft billionaire Paul Allen) â€¦ I’m pleased that new technologies and the opportunity to make this a global endeavor have the potential to greatly improve our search capability.” SETI Quest allows computer programmers to write code that can process data from the ATA. At a minimum, this will increase the chances of finding extraterrestrial intelligence.
But What About Non-Intelligent Life
So are 100-1 odds on finding intelligent life a good bet? What should the odds be? Dr. Tarter says “I don’t give odds. I don’t know the answer. The only reasonable thing to do is (to) do the experiment.”
So what about other life: bugs, bacteria? And what would finding alien life mean to the search for extraterrestrial intelligence. Dr. Shostak says “I think finding life of any variety (including DEAD pond scum) would galvanize SETI, simply because it would be a demonstration that biology, at least, is not a miracle!” In other words, such a discovery would change the betting odds dramatically.
Do you know what the betting odds are for finding any kind of life? Here are some things to consider before placing your bets.
Life Started Quickly on Earth
For Dr. David Morrison, the likelihood of finding life off of this planet has to do with how you see life in general. If you think life came about as a “natural process” then life is probably pretty likely. If you think life was “seeded by little green men” then life is less likely.
One strong reason for thinking that life is a natural process is that it started on Earth so easily. This planet was barely formed, a recently solidified orb 4 billion years ago. So far, scientists can show that life existed 3.55 billion years ago and it is likely that boundary could be pushed back. Not only did life start quickly but it persisted through a number of extinction events.
The Ubiquity of Watery Worlds
Life has very few prerequisites. Although we can find life almost everywhere on Earth, one requirement appears to be water. It seems that life requires plumbing and plumbing doesn’t work without a fluid.
Thus, alien locations that might have life are likely to need water. Fortunately, we see water in many places. Recently, we have discovered that the moon has so much water it actually must have some kind of water cycle. As NASA’s Brian Day says, “This isn’t your father’s moon anymore”. Also, the Cassini spacecraft in orbit around Saturn has found geysers of water on the moon Enceladus. Water is also present on Mars, some of Jupiter’s moons (Europa, Callisto, Ganymede) and the Saturnian moon Titan. It may exist on one or more moons of Uranus (Titania may have liquid water located at the core-mantle boundary) and Neptune (Triton may have a subterranean ocean like Europa). Today Venus is dry but that’s because it has been losing hydrogen and oxygen atoms for most of its 4.5 billion year existence. The European spacecraft Venus Express finds that twice as many hydrogen atoms as oxygen atoms are escaping the planet. Hmm, 2 parts hydrogen, 1 part oxygen. Sound familiar?
This suggests that liquid water might be available in 6 of 8 recognized planet-moon systems with only Venus and Mercury left out. So the chances of finding water are 75% if the rest of the galaxy is similar to our neighborhood.
Extremophiles Expand the Possibilities
If water is one requirement for life then the next requirement has to do with temperature. After all, water is a plumbing requirement and it is difficult to do much plumbing with ice and steam. But the range of temperatures and pressures where life can exist is growing all the time. Scientists have found primitive life forms ranging from Antarctica to very hot springs at the bottom of the ocean.
Richard Hoover of NASA has been studying bacteria under very cold conditions. Some bacteria can not only survive but thrive at temperatures down to -40°C, maybe even -80°C. Hoover says “Possibly what is going on is these microorganisms are melting the ice as the result of antifreeze proteins. They might look frozen but if it can melt the ice then the microorganism has all of the organics that it needs for metabolic activity.” Not only that, but some bacteria have been found in ice that has been frozen solid for 32,000 years. Some bacteria that has been in solid ice, when the ice is melted, the bacteria start moving around immediately. Hoover says “I think it is a common phenomenon that bacteria stay in a living state down to -40°C.” This means that comets might not only have bacterial fossils, but could have living bacteria on them.
The Best Bet of All
The odds of alien life are improving on various fronts. The range of environments where we know that life can exist is growing. Our ability to detect life, intelligent and otherwise, is growing. The odds of finding alien life keep improving.
Remember the bookmaking firm William Hill? They also give odds on finding life (of any sort) on Mars. When you don’t look for intelligence the odds are quite different. In fact at 4-6, life on Mars is an odds-on favorite.
What would the odds be on finding alien life anywhere, even on a meteorite? It is starting to sound like a sure thing.
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